A development blog of what Con Kolivas is doing with code at the moment with the emphasis on linux kernel, MuQSS, BFS and -ck.

Tuesday, 29 March 2011

2.6.38-ck1, BFS 0.363

So I screwed up. Sorry!

BFS 370 causes some strange regressions as per this blog and offlist. It appears that F&H doesn't, for example, scale to multiple CPUs under BFS 370. Also some latency regressions were reported here (and elsewhere). So I've decided to pull BFS 370 and 2.6.38-ck2, pending further investigation. There's only so much I can do without lots of people testing, I'm afraid, and often I get 1 maybe 2 people testing before a "stable" release, and then get about 10,000 downloads once the stable release comes out. So it was with test2/BFS370. Anyway the point is, go back to 2.6.38-ck1 or BFS 363 till I figure out what the problem was and decide whether it's worth pursuing this avenue or not.

hey ck, sorry not getting back to you sooner regarding the patch. The build got stuck on a bad builder, and it took a couple days to sort out.

I'm working on packaging for an Ubuntu ppa. I've been working on streamlining my packaging process so that I can push out patched packages much more quickly, and maybe get you some more testers!

Anyway, my test results for this patch were lackluster too. I was testing on the kraken benchmark, comparing conservative vs ondemand vs full speed. I didn't notice a whole lot of difference. With or without the patch I got about 15.5s for conservative, 21 for ondemand, and 14.5 for full speed.

I realize that we may be looking at different issues. I'm not knowledgeable enough to say. I cued in on the reference to frequency governors. I reported my issue to kernel.org and they came back with the tunable sampling_down_factor. It looks very promising for my issue. I've just started testing it. It might be of interest to you too.

Up today early testers only can test using their feelings or their hand touching the machine to feel the temperature. If we would have some easy tool to measure differences there would be lots more feedback for Con Kolivas! And surely more fun for testers to see results...

Hmm no idea, sorry. You'd have to compare it to a 2.6.38.2 kernel from elsewhere to see whether the problem is in -ck, my package, or 2.6.38. You could always try the 2.6.35.11 package instead. 2.6.38. is still pretty new.